Sealing device for roll bearings with compensation for radial offset

ABSTRACT

The invention relates to a sealing device for roll bearings in which a sealing element ( 9, 10 ) that interacts with a sealing surface is assigned to the rollpin ( 2 ). The aim of the invention is to improve a sealing device of this type so that a radial offset in the roll bearing results without significantly subjecting the sealing lip of the sealing element to stress. To this end, the sealing element is supported on the fixing device ( 8 ) thereof by means of an elastic supporting element ( 13 ), whereby the elastic supporting element has a rigidity less than that of the sealing lip ( 14, 15 ) of the sealing element.

[0001] The invention relates to a seal assembly for sealing the roll side of a roll bearing wherein at least one elastic seal element on the roll stub rides on an annular seal surface, the seal element and seal surface being mounted on respective supports one of which is stationary and the other of which is movable with the roll stub.

[0002] Such seal assemblies have long been used in oil-film bearings. As a rule expensive seal elements are used which on the one hand prevent oil from getting from the oil-film bearing to the roll body and on the other hand prevent particle-carrying coolant and lubricant from getting from the roll body into the oil-film bearing.

[0003] As a result of the various loads encountered during rolling, the roll stub can get radially offset in its mount. In unloaded nonworking rolls the seal space between the roll-stub sleeve and the bearing sleeve is less in a lower region, whereas the gap is greater in the opposite upper region. If the roll is working and pressure is being exerted from the mount through the bearing to the roll, the bearing gap between the roll-stub sleeve and the bearing sleeve is greater in the lower region whereas in the opposite upper region it decreases. This radial offset created by different loads must be compensated out by the seal elements.

[0004] As a result when the roll is not under load the seal lips in the lower region of the seal element are pushed together, while the seal lips in the upper region barely touch the seal surface. When the roll is working the seal lips are on the contrary pushed together a great deal in the upper region of the seal element and in the lower region barely touch the seal surface.

[0005] This radial play therefore creates a considerable load and as a result wear of the seal on the one hand from being squeezed together and on the other hand from the constant load change and furthermore the danger that the sealing effectiveness is not optimal with respect to the seal surface engaged by the seal lips.

[0006] It is an object of the invention to provide such a seal assembly that in spite of radial offset of the roll-stub sleeve in the bearing sleeve the seal lips of the seal element always optimally engage the seal surface without over stressing the seal elements and while reducing wear of the seal elements and increasing their service lives.

[0007] The invention attains this object in that the seal element and/or the seal surface are supported by at least one elastic support element on the holder, the elastic support element being less stiff than the seal lips of the seal element. In this system, when there is a radial offset, the seal lip of the seal element is not changed in shape in a smaller seal gap, but as a result of its greater stiffness the forces are applied to the elastic support element carrying the seal element, which is compressed in this region of the seal gap. On the opposite side, the elastic support element can expand in the larger seal gap so that here also the seal lip sits without substantial movement in an optimal manner on the seal surface.

[0008] It has been found advantageous when the stiffness of the elastic support element and/or the extent of radial compensation movement of the elastic support element are presettable. In this manner on the one hand seal elements of different stiffness can be accommodated while on the other hand the elastic support element changes shape to accommodate the expected radial offset.

[0009] It is preferable when the seal element and/or the seal surface is retained in its holder between at least one clamp body and if necessary an abutment, the clamping permitting a radial movement of the seal elements and/or of the seal surface, angular movement of the seal element being prevented. In this manner, for example a stationary seal element is not entrained by friction with the seal surface while being able to follow radial movement.

[0010] The elastic support element can be an O-ring or closed-end tube that e.g. is filled with an elastomer so as to ensure an optimal equalization of radial offset.

[0011] It is simpler to make and replace the seal element and the elastic support element when the elastic support element is integrated in the seal element, forming with it one part or piece.

[0012] It is preferable when the clamp body and if necessary the extension and/or the surface of the seal element and/or the seal surface that engage the abutment and if necessary the abutment are coated with Teflon. This makes possible radial movement of the seal element or of the seal surface in its holder.

[0013] To prevent the seal element and/or the seal surface from moving angularly in addition to radially, it is recommended that at least the clamp body and the surface of the seal element and/or the seal surface that engages the clamp body, have a radially extending toothing or guides that engage each other without substantial friction.

[0014] The invention is described more closely with reference to a drawing.

[0015] Therein:

[0016]FIG. 1 is a view of a roll with an oil-film bearing and

[0017]FIG. 2 is a detail of the seal.

[0018]FIG. 1 shows a roll 1 having a roll stub 2. The roll stub 2 is supported as shown in FIG. 2 by a roll-stub sleeve 3 in a bearing sleeve 4 which in turn is carried by a mount 5. The roll-stub sleeve 3 carries a roll-stub sleeve extension 6 having a seal surface 7. The mount carries a holder 8 that in turn carries seal elements 9 and 10. The seal elements 9 and 10 themselves are pressed by a clamping body 11 against an abutment 12 such that the seal elements 9 and 10 can move radially but not angularly in the holder 8. Between the holder 8 and the seal elements 9 and 10 is an elastic support element 13. The elastic support element 13 is formed as a closed tube filled with an elastomer.

[0019] If there is any radial offset between the roll stub 2 and the roll-stub sleeve 3 on one side and the bearing sleeve 4 and the mount 5 on the other, the seal elements 9 and 10 compensate out this radial offset. Since the elastic element 13 is not as stiff as the lips 14 and 15 of the seal element 9 and 10, the elastic support element 13 can take up the radial offset without substantial bending of the seal lips 14 and 15. This ensures that the seal lips 14 and 15 are always seated on the seal surface 7 for optimal sealing. In addition with this positioning of the lips 14 and 15 there is minimal wear.

[0020] The illustrated embodiment shows only that the seal elements 9 and 10 are supported by the elastic support element 13. It is also within the scope of the invention that such an elastic support element be provided between the seal surface 7 and the roll-stub extension 6, or that both the seal element and the seal surface are supported by respective elastic support elements.

Reference Numeral List

[0021]1 Roll

[0022]2 Roll stub

[0023]3 Stub sleeve

[0024]4 Bearing sleeve

[0025]5 Mount

[0026]6 Roll-stub sleeve extension

[0027]7 Seal surface

[0028]8 Holder

[0029]9 Seal element

[0030]10 Seal element

[0031]11 Clamp body

[0032]12 Abutment

[0033]13 Elastic support element

[0034]14 Seal lip

[0035]15 Seal lip 

1. A seal assembly for sealing the roll side of a roll bearing wherein at least one elastic seal element (9, 10) on the roll stub (2) rides on an annular seal surface (7), the seal element (9, 10) and seal surface (7) being mounted on respective supports (8, 6) one of which is stationary and the other of which is movable with the roll stub (2), characterized in that the seal element (9, 10) and/or the seal surface (7) are supported by at least one elastic support element (13) on the holder (8), the elastic support element (13) being less stiff than the seal lips (14 and 15) of the seal element (9, 10).
 2. The seal assembly according to claim 1, characterized in that the stiffness of the elastic support element (13) and/or the extent of radial compensation movement of the elastic support element (13) are presettable.
 3. The seal assembly according to claim 1 or 2, characterized in that the seal element (9, 10) and/or the seal surface (7) is retained in its holder (8) between at least one clamp body (11) and if necessary an abutment (12), the clamping permitting a radial movement of the seal elements (9, 10) and/or of the seal surface (7), angular movement of the seal element (9, 10) being prevented.
 4. The seal assembly according to one of claims 1 to 3, characterized in that the elastic support element (13) is at least one O-ring.
 5. The seal assembly according to one of claims 1 to 3, characterized in that the elastic support element (13) is a closed end tube.
 6. The seal assembly according to claim 4 or 5, characterized in that the elastic support element (13) is a tube or O-ring filled with an elastomer.
 7. The seal assembly according to one of claims 1 to 6, characterized in that the elastic support element (13) is unitarily formed with the seal element (9, 10).
 8. The seal assembly according to one of claims 1 to 7, characterized in that the clamp body (11) and if necessary the extension (12) and/or the surface of the seal element (9, 10) and/or the seal surface (7), that engage the abutment (12) and if necessary the abutment (12) are coated with Teflon.
 9. The seal assembly according to one of claims 1 to 8, characterized in that at least the clamp body (11) and the surface of the seal element (9, 10) and/or the seal surface that engages the clamp body (11), have a radially extending toothing or guides.
 10. The seal assembly according to one of claims 1 to 9, characterized in that the seal element (9, 10) is a gland-type seal.
 11. The seal assembly according to one of claims 1 to 10, characterized in that two seal elements (9 and 10) are provided on the holder (8). 